The utils.http.is_safe_url function in Django before 1.4.20, 1.5.x, 1.6.x before 1.6.11, 1.7.x before 1.7.7, and 1.8.x before 1.8c1 does not properly validate URLs, which allows remote attackers to conduct cross-site scripting (XSS) attacks via a control character in a URL, as demonstrated by a \x08javascript: URL.
https://www.djangoproject.com/weblog/2015/mar/18/security-releases/
http://www.securityfocus.com/bid/73319
http://www.oracle.com/technetwork/topics/security/bulletinapr2015-2511959.html
http://www.debian.org/security/2015/dsa-3204
http://ubuntu.com/usn/usn-2539-1
http://lists.opensuse.org/opensuse-updates/2015-09/msg00035.html
http://lists.opensuse.org/opensuse-updates/2015-04/msg00001.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-June/160263.html
http://lists.fedoraproject.org/pipermail/package-announce/2015-April/155421.html